Five psychiatric nurses at Áras Attracta are due to find out today if the HSE will be stopped from carrying out an internal investigation into alleged abuse at the Co Mayo facility.
None of them are facing any criminal charges, but were suspended after certain allegations arose following an investigative piece by RTÉ.
The women claim the process is "unfair" and goes against agreed procedures with the Psychiatric Nurses Association.
They are seeking an injunction preventing the internal investigation from going ahead, pending a full hearing on its legitimacy.
The HSE insists the investigation is not a disciplinary action, and has urged the High Court to allow them proceed.